We have previously described our sampling, enumeration, visual acuity, and ocular examination procedures [ 23, 24].
A detailed description of the sampling, enumeration, visual acuity and ocular examination procedures has already been published.
We used the McNemar test for related samples enumeration data and Chi-square test or the Fisher exact test for independent samples enumeration data and the Student t test for independent sample measurement data (normal continuous variables) and Wicoxon Singed-Rank test for related samples measurement data.
A two-stage sampling procedure was involved, the GSS sampled 66 enumeration areas (EAs) and Probability sampling proportional to population size was used, all women age 15 49 years in sampled households were eligible to be interviewed using a structured questionnaire.
In each country, we selected a stratified last stage random sample of enumeration areas (EA) of the most recent census, stratified by rural, urban, and capital location.
The study used a multistage sampling design that first selected a random sample of enumeration areas and then selected a random sample of households systematically from a household listing of all households in the enumeration area.
Participants were all residents in a stratified last stage random sample of enumeration areas 17 (the geographic area canvassed by one census representative) from the latest censuses, with 60 clusters in Nicaragua and 90 in Mexico.
In 2002, cross-sectional household surveys in a stratified urban/rural last-stage random sample of enumeration areas, based on latest national census in Botswana, Lesotho, Malawi, Mozambique, Namibia, Swaziland, Zambia and Zimbabwe.
Sampling and enumeration of the inoculated samples were done at protocol-defined time points through 28 days (Table 1) [ 11].
A second is the difficulty of gaining school-district approval to access elementary school populations, necessitating the use of targeted-age directory sampling or household enumeration sampling methods.
For example, the DHS uses cluster-sampling to draw upon women respondents via multistage sampling of enumeration areas.
